20123540 has 12 divisors (see below), whose sum is σ = 42259476. Its totient is φ = 8049408.

The previous prime is 20123539. The next prime is 20123549. The reversal of 20123540 is 4532102.

It can be written as a sum of positive squares in 2 ways, for example, as 14032516 + 6091024 = 3746^2 + 2468^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20123549) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 503069 + ... + 503108.

It is an arithmetic number, because the mean of its divisors is an integer number (3521623).

Almost surely, 2^20123540 is an apocalyptic number.

20123540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20123540 is an abundant number, since it is smaller than the sum of its proper divisors (22135936).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20123540 is a wasteful number, since it uses less digits than its factorization.

20123540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1006186 (or 1006184 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 17.

The square root of 20123540 is about 4485.9268830421. The cubic root of 20123540 is about 271.9995134074. Note that the first 3 decimals are identical.

Adding to 20123540 its reverse (4532102), we get a palindrome (24655642).

The spelling of 20123540 in words is "twenty million, one hundred twenty-three thousand, five hundred forty".